The objectives of this project are: 1. Determine and analyze the various mechanisms that affect the coupling and transmission of vibration from a vibrating tool handle into the hand and arm. 2. Determine the subjective response characteristics of a healthy student tesD population to hand induced vibration for various methods of clasping a vibrating handle. These tests are to be conducted using discrete and 1/3 octave band vibration signals. 3. Determine if there are any measureable differences with respect to the mechanical and subjective response characteristics due to hand induced vibration between a known healthy student test population and test populations consisting of workers who have not been exposed to hand induced vibration and of workers who have been exposed to hand induced vibration. These objectives will be met by exciting the hands of the test subjects with a .75 in dia handle attached to an electromagnetic shaker. Transmissibility, mechanical impedance and equal sensation values will be measured and compared between the various test groups.